Question

Write the equation in standard form of the line that has x-intercept 9 and y-intercept -9

Answer 1

`\stackrel{ x-intercept }{(\stackrel{x_1}{9}~,~\stackrel{y_1}{0})}\qquad \stackrel{ y-intercept }{(\stackrel{x_2}{0}~,~\stackrel{y_2}{-9})} ~\hfill \stackrel{slope}{m}\implies \cfrac{\stackrel{\textit{\large rise}} {\stackrel{y_2}{-9}-\stackrel{y1}{0}}}{\underset{\textit{\large run}} {\underset{x_2}{0}-\underset{x_1}{9}}} \implies \cfrac{ -9 }{ -9 } \implies \cfrac{1}{1}\implies 1`

`\begin{array} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{0}=\stackrel{m}{ 1}(x-\stackrel{x_1}{9})\implies {\Large \begin{array}{llll} y=x-9 \end{array}}`